CATEGORIES OF COMPUTERS Industry experts typically classify computers in seven categories: i. Personal computers (desktop) ii. mobile computers and mobile devices iii. game consoles iv. servers v. mainframes vi. supercomputers, and vii. embedded computers. A computer’s size, speed, processing power, and price determine the category it best fits. Due to rapidly changing technology, however, the distinction among categories is not always clear-cut. This trend of computers and devices with technologies that overlap, called convergence, leads to computer manufacturers continually releasing newer models that include similar functionality and features. For example, newer cell phones often include media player, camera, and Web browsing capabilities. As devices converge, users need fewer devices for the functionality that they require. When consumers replace outdated computers and devices, they should dispose of them properly. Categories of Computers Category Physical Size Number of General Price Range Simultaneously Connected Users Personal computers Fits on a desk Usually one (can be Several hundred to (desktop) more if networked) several thousand dollars Mobile computers and Fits on yo ur lap or in Usually one Less than a hundred mobile devices your hand dollars to several thousand dollars Game consoles Small box or handheld One to several Several hundred dollars device or less Servers Small cabinet Two to thousands Several hundred to a million dollars Mainframes Partial room to a full Hundreds to thousands $300,000 to several room of equipment million dollars Supercomputers Full room of equipment Hundreds to thousands $500,000 to several billion dollars Embedded computers Miniature Usually one Embedded in the price of the product Personal Computers A personal computer is a computer that can perform all of its input, processing, output, and storage activities by itself. A personal computer contains a processor, memory, and one or more input, output, and storage devices. Personal computers also often contain a communications device. Two popular architectures of personal computers are the PC and the Apple. The term, PC-compatible, refers to any personal computer based on the original IBM personal computer design. Companies such as Dell, HP, and Toshiba sell PC-compatible computers. PC and PC-compatible computers usually use a Windows operating system. Apple computers usually use a Macintosh operating system (Mac OS). Two types of personal computers are i. desktop computers, and ii. notebook computers Desktop Computers : A desktop computer is designed so that the system unit, input devices, output devices, and any other devices fit entirely on or under a desk or table. In many models, the system unit is a tall and narrow tower, which can sit on the floor vertically — if desktop space is limited. Some desktop computers function as a server on a network. Others, such as a gaming desktop computer and home theatre PC, target a specific audience. The gaming desktop computer offers high-quality audio, video, and graphics with optimal performance for sophisticated single-user and networked or Internet multiplayer games. A home theatre PC (HTPC) combines the features of a high-definition video/audio entertainment system with a desktop computer that is designed to be connected to a television and includes a Blu-ray Disc, digital video recorder, and digital cable television connectivity. These high-end computers cost more than the basic desktop computer. Another expensive, powerful desktop computer is the workstation, which is geared for work that requires intense calculations and graphics capabilities. An architect uses a workstation to design buildings and homes. A graphic artist uses a workstation to create computer-animated special effects for full-length motion pictures and video games. Notebook Computers : A notebook computer, also called a laptop computer, is a portable, personal computer often designed to fit on your lap. Notebook computers are thin and lightweight, yet they can be as powerful as the average desktop computer. A netbook, which is a type of notebook computer, is smaller, lighter, and often not as powerful as a traditional notebook computer. Most netbooks cost less than traditional notebook computers, usually only a few hundred dollars. An ultra-thin is another type of notebook computer that is lightweight and usually less than one-inch thick. Some notebook computers have touch screens, allowing you to interact with the device by touching the screen, usually with the tip of a finger. On a typical notebook computer, the keyboard is on top of the system unit, and the monitor attaches to the system unit with hinges. These computers weigh on average from 2.5 to more than 10 pounds (depending on configuration), which allows users to transport the computers from place to place. This is the reason why even though the Notebook is a type of Personal Computer; it is also a mobile computer. Most notebook computers can operate on batteries or a power supply or both. Mobile Computers and Mobile Devices A mobile computer is a personal computer you can carry from place to place. Similarly, a mobile device is a computing device small enough to hold in your hand. The most popular type of mobile computer is the notebook computer, which has been discussed above. Tablet PCs : Resembling a letter-sized slate, the Tablet PC, or tablet computer, is a special type of notebook computer that you can interact with by touching the screen with your finger or a digital pen. A digital pen looks like a small ink pen but uses pressure instead of ink. Users write or draw on a Tablet PC by pressing a finger or digital pen on the screen, and issue instructions by tapping on the screen. One design of Tablet PC, called a convertible tablet, has an attached keyboard. Another design, which does not include a keyboard, is called a slate tablet (for example iPad) and provides other means for typing. Some Tablet PCs also support voice input so that users can speak into the computer. Tablet PCs are useful especially for taking notes in lectures, at meetings, conferences, and other forums where the standard notebook computer is not practical. Mobile Devices Mobile devices, which are small enough to carry in a pocket, usually do not have disk drives. Instead, these devices store programs and data permanently on special memory inside the system unit or on small storage media such as memory cards. You often can connect a mobile device to a personal computer to exchange information between the computer and the mobile device. Some mobile devices are Internet-enabled, meaning they can connect to the Internet wirelessly. With an Internet-enabled device, users can chat, send e-mail and instant messages, and access the Web. Because of their reduced size, the screens on mobile devices are small, but usually are in colour. Popular types of mobile devices are smart phones and PDAs, e-book readers, handheld computers, portable media players, and digital cameras. Smart Phones and PDAs : Offering the convenience of one-handed operation, a smart phone is an Internet-enabled phone that usually also provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad. In addition to basic phone capabilities, a smart phone allows you to send and receive e-mail messages and access the Web — usually for an additional fee. Some smart phones communicate wirelessly with other devices or computers. Many also function as a portable media player and include built-in digital cameras so that you can share photos or videos with others as soon as you capture the image. Many smart phones also offer a variety of application software such as word processing, spreadsheet, and games, and the capability of conducting live video conferences. Many smart phones have keypads that contain both numbers and letters so that you can use the same keypad to dial phone numbers and enter messages. Others have a built-in mini keyboard on the front of the phone or a keyboard that slides in and out from behind the phone. Some have touch screens, where you press objects on the screen to make selections and enter text through an on-screen keyboard. Others include a stylus, which is similar to a digital pen but smaller and has less functionality. Instead of calling someone’s smart phone or cell phone, users often send messages to others by pressing buttons on their phone’s keypad, keys on the mini keyboard, or images on an onscreen keyboard. Types of messages users send with smart phones include text messages, instant messages, picture messages, and video messages. • A text message is a short note, typically fewer than 300 characters, sent to or from a smart phone or other mobile device. • An instant message is a real-time Internet communication, where you exchange messages with other connected users. • A picture message is a photo or other image, sometimes along with sound and text, sent to or from a smart phone or other mobile device. A phone that can send picture messages often is called a camera phone. • A video message is a short video clip, usually about 30 seconds, sent to or from a smart phone or other mobile device. A phone that can send video messages often is called a video phone. A PDA (personal digital assistant), which often looks like a smart phone, provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad. A PDA differs from a smart phone in that it usually does not provide phone capabilities and may not be Internet-enabled, support voice input, have a built-in camera, or function as a portable media player. As smart phones and PDAs continue a trend of convergence, it is becoming increasingly difficult to differentiate between the two devices.